Piece of Audio gear you regret selling

Ebm, you are a human being after all. Welcome.
I too regret buing certain things. I should've waited and bought more serious analog front end in the first place instead of getting entry level to start with. Made no sense and I lost some money.
The subject of dealers and manufacturers participating in this forum, openly or not, is a controversial one. I started the thread about it some time ago which did not get through the moderator.

Blue Circle BC-3000.

Lavardin IT, changed it for a Karan K180, not a patch on the Lavardin

My TT. Not because it sounded so great when I had it on my then lo-lo-lo-fi system. But because had I kept it I'd have kept all of my albums. Had I done that, today I'd get a decent TT for my now hi-fi system. Dumping my albums for the panacea of CDs was THE biggest mistake of my audio life.

Sold my Aesthetix Calypso with NOS tubes for $2300, only to buy the Signature version Calypso a few months later.

I did the same! It is a wonderful pre. Just wish it had a 12v trigger out.